Wafer-scale ultrathin and uniform van der Waals ferroelectric oxide
Qinci Wu, Zhongrui Li, Bingchen Han, Weiyu Sun, Qinyun Liu, Chengyuan Xue, Hyeonhu Bae, Mengdi Wang, Boyang Fu, Jun Qian, Yongchao Zhu, Yu Sun, Tingkai Feng, Xin Gao, Xuzhong Cong, Wanqing Liu, Yunan Gao, Binghai Yan, Congwei Tan, Hongtao Liu, Hailin Peng
Abstract
Ferroelectrics have great potential for nonvolatile memory and next-generation electronics, but conventional ferroelectric oxide films generally suffer structural nonuniformity, interfacial depolarization, and performance degradation, particularly when downscaled to advanced technology nodes. We demonstrate uniform, wafer-scale synthesis and back-end-of-line–compatible integration of ultrathin van der Waals (vdW) high-dielectric constant ferroelectric oxide Bi 2 SeO 5 , retaining an optimal coercive field and robust ferroelectricity at monolayer thickness. Ultrathin vdW ferroelectric oxides formed atomically uniform interfaces with two-dimensional semiconductors and yielded ferroelectric field-effect transistor (FeFET) arrays with a low operating voltage (0.8 volts), exceptional cycling endurance (>1.5 × 10 12 cycles), fast write speed (20 nanoseconds), high on/off ratio (10 6 ), 10-year retention, ultralow energy consumption (2.8 femtojoules per bit per square micrometer), and <5% device-to-device variation. Reconfigurable logic-in-memory circuits with these FeFETs function at supply voltages of <1 volt.